package com.jecy.utils;

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.spec.SecretKeySpec;
import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.SecureRandom;

/**
 * TODO 一句话描述该类用途
 * <p/>
 * 创建时间: 15/10/21 下午4:38<br/>
 *
 * @author qyang
 * @since v0.0.1
 */
public class AESUtil {

    /**
     * 编码工具类
     * 1.将byte[]转为各种进制的字符串
     * 2.base 64 encode
     * 3.base 64 decode
     * 4.获取byte[]的md5值
     * 5.获取字符串md5值
     * 6.结合base64实现md5加密
     * 7.AES加密
     * 8.AES加密为base 64 code
     * 9.AES解密
     * 10.将base 64 code AES解密
     * @author uikoo9
     * @version 0.0.7.20140601
     */

        public static void main(String[] args) throws Exception {



            String content = "我爱你";
            System.out.println("加密前：" + content);

            String key = "123456";
            System.out.println("加密密钥和解密密钥：" + key);

            String encrypt = aesEncrypt(content, key);
            System.out.println("加密后：" + encrypt);

            String decrypt = aesDecrypt(encrypt, key);
            System.out.println("解密后：" + decrypt);
        }

        /**
         * 将byte[]转为各种进制的字符串
         * @param bytes byte[]
         * @param radix 可以转换进制的范围，从Character.MIN_RADIX到Character.MAX_RADIX，超出范围后变为10进制
         * @return 转换后的字符串
         */
        public static String binary(byte[] bytes, int radix){
            return new BigInteger(1, bytes).toString(radix);// 这里的1代表正数
        }

        /**
         * base 64 encode
         * @param bytes 待编码的byte[]
         * @return 编码后的base 64 code
         */
        public static String base64Encode(byte[] bytes){
            return new BASE64Encoder().encode(bytes);
        }

        /**
         * base 64 decode
         * @param base64Code 待解码的base 64 code
         * @return 解码后的byte[]
         * @throws Exception
         */
        public static byte[] base64Decode(String base64Code) throws Exception{
            return new BASE64Decoder().decodeBuffer(base64Code);
        }

        /**
         * 获取byte[]的md5值
         * @param bytes byte[]
         * @return md5
         * @throws Exception
         */
        public static byte[] md5(byte[] bytes) throws Exception {
            MessageDigest md = MessageDigest.getInstance("MD5");
            md.update(bytes);

            return md.digest();
        }

        /**
         * 获取字符串md5值
         * @param msg
         * @return md5
         * @throws Exception
         */
        public static byte[] md5(String msg) throws Exception {
            return md5(msg.getBytes());
        }

        /**
         * 结合base64实现md5加密
         * @param msg 待加密字符串
         * @return 获取md5后转为base64
         * @throws Exception
         */
        public static String md5Encrypt(String msg) throws Exception{
            return base64Encode(md5(msg));
        }

        /**
         * AES加密
         * @param content 待加密的内容
         * @param encryptKey 加密密钥
         * @return 加密后的byte[]
         * @throws Exception
         */
        public static byte[] aesEncryptToBytes(String content, String encryptKey) throws Exception {
            KeyGenerator kgen = KeyGenerator.getInstance("AES");
            SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG");
            secureRandom.setSeed(encryptKey.getBytes());
            kgen.init(128, secureRandom);

            Cipher cipher = Cipher.getInstance("AES");
            cipher.init(Cipher.ENCRYPT_MODE, new SecretKeySpec(kgen.generateKey().getEncoded(), "AES"));

            return cipher.doFinal(content.getBytes("utf-8"));
        }

        /**
         * AES加密为base 64 code
         * @param content 待加密的内容
         * @param encryptKey 加密密钥
         * @return 加密后的base 64 code
         * @throws Exception
         */
        public static String aesEncrypt(String content, String encryptKey) throws Exception {
            return base64Encode(aesEncryptToBytes(content, encryptKey));
        }

        /**
         * AES解密
         * @param encryptBytes 待解密的byte[]
         * @param decryptKey 解密密钥
         * @return 解密后的String
         * @throws Exception
         */
        public static String aesDecryptByBytes(byte[] encryptBytes, String decryptKey) throws Exception {
            KeyGenerator kgen = KeyGenerator.getInstance("AES");
            SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG");
            secureRandom.setSeed(decryptKey.getBytes());
            kgen.init(128, secureRandom);

            Cipher cipher = Cipher.getInstance("AES");
            cipher.init(Cipher.DECRYPT_MODE, new SecretKeySpec(kgen.generateKey().getEncoded(), "AES"));
            byte[] decryptBytes = cipher.doFinal(encryptBytes);

            return new String(decryptBytes);
        }

        /**
         * 将base 64 code AES解密
         * @param encryptStr 待解密的base 64 code
         * @param decryptKey 解密密钥
         * @return 解密后的string
         * @throws Exception
         */
        public static String aesDecrypt(String encryptStr, String decryptKey) throws Exception {
            return aesDecryptByBytes(base64Decode(encryptStr), decryptKey);
        }

}
